Suicide bombers belonging to Taliban detonated bombs and fired rockets outside a major U.S. base in eastern Afghanistan on Sunday. Police said 12 bodies in Afghan police and military uniforms were found around the entrance of the airfield in the eastern city of Jalalabad, Reuters reported. However, it is not clear whether the dead were Afghan security forces or militants dressed in uniforms.

A spokesman for the NATO-led International Security Assistance Force (ISAF), Major Martyn Crighton told Reuters that multiple suicide bombers were involved in the attack during which an Afghan security staff was killed and several coalition troops were wounded.

The attack highlights the country's security challenges at a time when the NATO forces are in the process of handling security over to Afghan forces ahead of the 2014 combat troop pullout.

 "This morning at 6 a.m. a number of our devotees attacked the major U.S. Base in Jalalabad city and so far have brought heavy casualties to the enemy," Taliban claimed responsibility for the attack in a text message. According to an Associated Press report, Taliban spokesman Zabiullah Mujahid said the militants first exploded a car bomb at the entrance of the airfield and then stormed into the base. "First a fedayee (suicide bomber) mujahid detonated a car bomb causing the enemy heavy casualties and losses and removed all the barriers," the Taliban said on its website. "After the attack other fedayee mujahids entered the base... and started attacking the invading forces in the base."

An Afghan Defense Ministry spokesman, Gen. Mohammad Zahir Azimi confirmed that suicide car bombs were used at the entrance, but said none of the attackers were able to enter the base. "We can confirm insurgents, including multiple suicide bombers, attacked Jalalabad Airfield this morning. None of the attackers succeeded in breaching the perimeter," Lt. Col. Hagen Messer, a spokesman for the international military coalition, said in an email, AP reports.